The present disclosure relates to the re-sampling of pixel data, with one application being micro-lithography. In particular, it relates to the extraction of modulator pixels from a rasterized image, as a function of how the modulator moves across the rasterized image.
Micro-lithography is the process of writing a circuit design (so-called geometry) onto a workpiece having a radiation sensitive layer, typically either a photomask for use in exposing equipment or directly onto a wafer or substrate. The lithographic write equipment writes the geometry onto the workpiece, using a laser or charged beam to expose a resist layer. This exposure changes the molecular composition of the resist. During the developing process for a positive resist, any resist that has been exposed will be removed. In some applications, a negative resist is used where the resist that was not exposed will be removed in development.
Photomasks are high precision plates containing microscopic images of electronic circuits. Photomasks typically are made from very flat pieces of quartz or glass with a layer of chrome on one side. Etched in the chrome is a portion of an electronic circuit design. This circuit design on the mask is also sometimes called the geometry.
Photomasks are used in wafer fabrication, mostly to make ICs (integrated circuits). ICs are used in many products like computers, calculators, cars, cameras, and stereos. Photomasks are also used to make flat panel displays, thin film heads, PC boards, etc.
During development, a customer designs a circuit using tools that digitally store the information. The customer then sends the digitized data containing the design for each layer to the mask maker or direct writing vendor. The data can be sent on a disk, magnetic tape, via Internet or dedicated lines.
The mask maker takes the customer's data and formats it for the actual tools or systems in which the masks will be made. This includes fracturing the data, sizing the data if needed, rotating the data if needed, adding fiducials and internal reference marks, and making a jobdeck, which includes instructions for the placement of all the different patterns on the mask.
Fracturing the data means translating the customer data into a language the write tool can understand. The write system typically uses rectangles, trapezoids and/or triangles. The customer data is divided up (fractured) into these shapes. The jobdeck with the fractured data is put on a data media and sent to the write area or pulled directly to the machines using network software.
Before the pattern can be printed, additional pattern processing is needed. The geometries are spatially reorganized to match the writing sequence of the tool. For some systems, this means rendering the geometries into pixels to be imaged by the exposure system. For other systems, this means translating the geometries into a format appropriate for vector shaped beams (VSBs) or laser scanning.
For a pixel-based exposure system, the number of pixels to be printed is proportional to the area the pattern cover. Even though the number of pixels is constant, there may be a significant difference in computational resources needed to process the pattern. Resource demands are heavily dependent on pattern, thus complicating component sizing of the pattern processing system.
For applications where same pattern is printed several times, either on the same mask/substrate (multipass printing) or on separate masks/substrates, it is desired to not repeat the entire pattern processing for each print, even though the actual pattern printed could differ from piece-to-piece.
The technology disclosed usefully addresses the two problems above for pixel-based exposure systems by introducing a data processing architecture using a processor to produce an intermediate pixel, a so-called Geometrical Pixel Map (GPM) from which the actual printed pixels, the so-called Modulator Pixel Map (MPM) is derived.
The data processing architecture is henceforth referred to as the data path. The data path is the combination of execution units, data transportation, data storage, software, firmware and algorithms, organized to transform the designer's description of the image to be printed by modulator pixels of writer systems.